Identification code sheets involved in an identification, there are known a bar code and a token code designed to represent a numerical character and/or a symbol.
As well known, the bar code is set up by a plurality of fine and thick bars spaced regularly and combined to represent a numerical character etc. According to the prior art, a sheet of bar code set up by a combination of a plurality of fine and thick bars spaced regularly is characteristically accompanied by drawbacks such as a need of high level techniques of printing on the sheet requiring unnecessarily high level of accuracy for preparation which is very costly.
Another sheet of token code type for binary representation in terms of the locations of punched hole is accompanied by such drawbacks as a need of punching process and a low speed of reading relative to an optical and or magnetic types.
Other drawbacks inherent to the above types of sheet are presently a limited capability of representing only a numerical character and a part of a character string, and a need of re-making the sheet whenever an urgent change of the code content is needed. This change is made by the operators by code printer or a punch installed elsewhere away from the site of operation. Therefore a substantial difficulty is encountered also in the data maintanance, especially for a large scale POS (Point Of Sales system).
There is also another known art represented by reading means to handle an identification code represented by a bar code system, according to U.S. Patent application No.316,936 (Japanese Patent Publication No.21980 of 1978).
According to the above described prior art, bar codes are to be identified as to encoded indicia on the principle of finding both a finess/thickness and a location of the code bars. This often resulting in a high likelihood of inducing reading errors. These types of codes are used mostly to represent, in general, the numerical characters and rarely can handle even the reading of alphabets. For this reason, the realization of these conventional means has not so far been achieved to cover a Kanzi-code under JIS (Japanese Industrial Standard) rule. According to the above described conventional art, there is also an absolute need for an exact reading of a finess/thickness and a location of the bars setting up bar codes. This means a likelihood of occurring reading errors to, depending on misprints of the code bars, elongation/shrinkage of the bar code papers, irregularity of the surfaces on which the bar code papers are to be pasted and a change in the reading angle of a sensor relative to the bar code paper.
More recently, a new method of code-making is being developed, by which 0 to F is represented by coding properly " " character. It should, however, be noted that " " character involves, in coding thereof, such unsolved problems as a need for addition thereto of a direction of reading and specification of the same, because of the symmetrical composition of the character in both horizontal and vertical directions.